This package has a configure.in file which has long been deprecated. Please update it to use configure.ac instead as newer versions of autotools will die when it finds this file. See https://bugs.gentoo.org/426262 for details.
File that triggers this warning is libdnet-stripped/configure.in and all versions are affected.
*** This bug has been marked as a duplicate of bug 426262 ***
This still exists on a fresh tree sync, I would not call it resolved. I also would not call it a duplicate, as there are many packages with this fault and reporting each package there would only clog up 426262 with useless information. Thank you.